From 585fba50b00b5716bbde7a1b05cbab114af8cdb0 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <mail@daniel-baumann.ch>
Date: Sat, 7 Nov 2015 12:53:03 +0100
Subject: Adding upstream version 1.18~pre2.

Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
---
 decoder.h | 51 +++++++++++++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 24 deletions(-)

(limited to 'decoder.h')

diff --git a/decoder.h b/decoder.h
index 5e6e16c..5ffc0be 100644
--- a/decoder.h
+++ b/decoder.h
@@ -19,12 +19,12 @@ class Range_decoder
   {
   enum { buffer_size = 16384 };
   unsigned long long partial_member_pos;
-  uint8_t * const buffer;	/* input buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* when reached, a new block must be read */
+  uint8_t * const buffer;	// input buffer
+  int pos;			// current pos in buffer
+  int stream_pos;		// when reached, a new block must be read
   uint32_t code;
   uint32_t range;
-  const int infd;		/* input file descriptor */
+  const int infd;		// input file descriptor
   bool at_stream_end;
 
   bool read_block();
@@ -214,12 +214,11 @@ class LZ_decoder
   unsigned long long partial_data_pos;
   Range_decoder & rdec;
   const unsigned dictionary_size;
-  const int buffer_size;
-  uint8_t * const buffer;	/* output buffer */
-  int pos;			/* current pos in buffer */
-  int stream_pos;		/* first byte not yet written to file */
+  uint8_t * const buffer;	// output buffer
+  unsigned pos;			// current pos in buffer
+  unsigned stream_pos;		// first byte not yet written to file
   uint32_t crc_;
-  const int outfd;		/* output file descriptor */
+  const int outfd;		// output file descriptor
 
   unsigned long long stream_position() const
     { return partial_data_pos + stream_pos; }
@@ -228,37 +227,42 @@ class LZ_decoder
 
   uint8_t peek_prev() const
     {
-    const int i = ( ( pos > 0 ) ? pos : buffer_size ) - 1;
+    const unsigned i = ( ( pos > 0 ) ? pos : dictionary_size ) - 1;
     return buffer[i];
     }
 
-  uint8_t peek( const int distance ) const
+  uint8_t peek( const unsigned distance ) const
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
+    unsigned i = pos - distance - 1;
+    if( pos <= distance ) i += dictionary_size;
     return buffer[i];
     }
 
   void put_byte( const uint8_t b )
     {
     buffer[pos] = b;
-    if( ++pos >= buffer_size ) flush_data();
+    if( ++pos >= dictionary_size ) flush_data();
     }
 
-  void copy_block( const int distance, int len )
+  void copy_block( const unsigned distance, unsigned len )
     {
-    int i = pos - distance - 1;
-    if( i < 0 ) i += buffer_size;
-    if( len < buffer_size - std::max( pos, i ) && len <= std::abs( pos - i ) )
+    unsigned i = pos - distance - 1;
+    bool fast;
+    if( pos <= distance )
+      { i += dictionary_size;
+        fast = ( len <= dictionary_size - i && len <= i - pos ); }
+    else
+      fast = ( len < dictionary_size - pos && len <= pos - i );
+    if( fast )					// no wrap, no overlap
       {
-      std::memcpy( buffer + pos, buffer + i, len );	// no wrap, no overlap
+      std::memcpy( buffer + pos, buffer + i, len );
       pos += len;
       }
     else for( ; len > 0; --len )
       {
       buffer[pos] = buffer[i];
-      if( ++pos >= buffer_size ) flush_data();
-      if( ++i >= buffer_size ) i = 0;
+      if( ++pos >= dictionary_size ) flush_data();
+      if( ++i >= dictionary_size ) i = 0;
       }
     }
 
@@ -275,13 +279,12 @@ public:
     partial_data_pos( 0 ),
     rdec( rde ),
     dictionary_size( header.dictionary_size() ),
-    buffer_size( std::max( 65536U, dictionary_size ) ),
-    buffer( new uint8_t[buffer_size] ),
+    buffer( new uint8_t[dictionary_size] ),
     pos( 0 ),
     stream_pos( 0 ),
     crc_( 0xFFFFFFFFU ),
     outfd( ofd )
-    { buffer[buffer_size-1] = 0; }	// prev_byte of first byte
+    { buffer[dictionary_size-1] = 0; }		// prev_byte of first byte
 
   ~LZ_decoder() { delete[] buffer; }
 
-- 
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